The invention also relates to a method for constructing the profile of a surface portion of a lever of the aforementioned brake.
Such a brake can be mounted on a bicycle frame both at the front wheel (in particular, on the fork of the frame) and at the rear wheel.
Typically, bicycle brakes comprise two levers that support respective brake pads. The two levers are controlled so as to clamp the brake pads around the rim of the front/rear wheel, to brake it. The clamping of the pads takes place following the actuation by the cyclist of a control lever (usually arranged at the ends of the handlebars) with which an end of a sheathed cable (Bowden cable) is associated, the other end of the sheathed cable being associated with the two levers of the brake.
In particular, the brake of the present invention has a first lever having an actuation arm connected to an inner cable of the sheathed cable and a second lever having an actuation arm connected to a sheath of the sheathed cable.
Three types of brakes of this kind are known: with single rotation axis and single fastening pin (hereafter, brake of type A), with double rotation axis and single fastening pin (hereafter, brake of type B), and with double rotation axis and double fastening pin (hereafter, brake of type C).
In the brake of type A, both of the levers are articulated around a single central pin, which also acts as fastening pin to the frame of the bicycle. In such a brake a single rotation axis of the two levers is thus defined (at the central pin).
In the brake of type B, one of the two levers (usually the lever connected to the sheath of the sheathed cable) is articulated around a central pin that also acts as fastening pin to the frame of the bicycle, whereas the other lever (usually the lever connected to the inner cable of the sheathed cable) is articulated around a second pin fixed on a support body in turn fixed to the central pin. In such a brake, two rotation axes are thus defined (at the two pins), only one of the pins (central pin) being associated with the frame of the bicycle.
In the brake of type C, each lever is articulated around a respective pin that also acts as fastening pin to the frame of the bicycle. In such a brake two rotation axes are thus defined (at the two pins), both of the pins being associated with the frame of the bicycle.
In all three of the aforementioned types of brakes, in the lever connected to the sheath of the sheathed cable, the attachment area to the aforementioned sheath (and therefore the actuation arm of such a lever) is arranged on the same side, with respect to the wheel, of the support area of the brake pad (and therefore of the braking arm of such a lever). Differently, in the lever connected to the inner cable of the sheathed cable, the attachment area to the aforementioned inner cable (and therefore the actuation arm of such a lever) is arranged on the opposite side, with respect to the wheel, of the support area of the brake pad (and therefore of the braking arm of such a lever).
Brakes of type A and B are disclosed, for example, by document WO 2007/063564 to the same Applicant.
Brakes of type C are available on market and are indicated in general with the expression: “direct mount” brakes.